Mark P. Taylor, Peter L. Timms, Geoffrey C. Allen and Simon R. Church
When hydrogen peroxide vapour and silane are mixed appropriately at low pressure a self-planarising layer of silica is formed by a surface phase reaction. The effect on the reaction of replacing part of the SiH4 with GeH4, PH3 and B2H6 has now been studied. Using GeH4-SiH4 mixtures containing up to 27 GeH4, self-planarising, Ge-Si-O films, rich in germanium were obtained. Films formed by oxidising the same GeH4-SiH4 mixtures with plasma cracked water vapour were not self-planarising and contained much less germanium. The mixed oxide films from reacting PH3-SiH4 or B2H6-SiH4 mixtures with H2O2 vapour were also not self-planarising but were spectroscopically similar to known phosphosilicate or borosilicate glasses.